The present invention relates to a mobile communication terminal such as a mobile telephone, pager, PHS, etc. that can prevent loss of information by storing necessary information when a low voltage operation occurs.
In the conventional mobile communication terminal, personal information such as a telephone directory and saved messages which are seldom updated and frequency information, address information, etc. which are updated many times but loss of which is not permitted are recorded in a nonvolatile storing medium such as a flash ROM, EEPROM, etc. whereas information (information items) such as time information, etc. which are updated many times are recorded in a volatile storing medium such as RAM, etc.
Also, as for the information stored in the volatile storing medium, loss of the information stored in the volatile storing medium such as RAM, etc. due to a low voltage operation is prevented by using a secondary battery, etc.
However, upon managing back-up information in the conventional mobile communication terminal, if the information items, e.g., time information, etc. which are updated many times are recorded in the nonvolatile storing medium such as EEPROM, etc., such nonvolatile storing medium is degraded and in turn the lifetime of the mobile communication terminal itself is affected, and thus it is difficult to realize such management. Also, if the update number of times is reduced, the time information, etc. which need a real-time property lose their value. Hence, there is no means except that such information are stored in the volatile storing medium such as RAM, etc.
Also, in order not to lose the information stored in the volatile storing medium such as RAM, etc., the secondary battery is needed. This results in the increase of cost of the mobile communication terminal.